This is the story of an ex-slave named Rutherford Calhoun. When his master, Peleg Chandler, who hated slavery, dies, Rutherford makes his way to New Orleans. He lives a rather dissipated existence as a gambler and a thief, enjoying himself thoroughly. One day, a friend (to whom he is not attracted) named Isadora Bailey makes a deal with Papa, a local criminal: she will pay all the debts Rutherford owes (to people who work for Papa) if Rutherford agrees to marry her—tomorrow. Left without a choice, Rutherford agrees. That night, however, he stows away on a ship docked nearby, the Republic, in order to escape the wedding.

When he is awoken, Rutherford begins to learn what a terrible mistake he has made. This is a slave ship, on its way to pick up members of a tribe in Africa that has been described as devil-worshipers. Further, the captain, Ebenezer Falcon, is a violent and possibly deranged sociopath, and most of the other men on the ship are escaping terrible crimes they've committed elsewhere. The journey to pick up the soon-to-be slaves goes normally, but all hell breaks loose once the slaves are on board the ship. To make matters worse, and stranger, Falcon claims to have captured one of their gods, whom he is holding below deck. Some of the crew plots to overthrow Falcon, with whom Rutherford has actually developed a rapport, but on the night of the planned mutiny, there is a horrible storm and the captured Africans revolt. Many of the crew die, and Falcon eventually kills himself. The entire population is damaged, disease-ridden, and starving. Rutherford is delirious, and the entire group must cannibalize the last people to die in order to survive. Soon, the ship begins to sink, and a few survivors are picked up by another ship full of rich people.

Here, Rutherford is shocked to see Papa and Isadora evidently preparing for their own wedding. He has been keeping a log of all of the events that have taken place, including the revelation that Papa, a black man, is actually one of the financiers of the slave ship. When Rutherford sees Isadora, he finds her to be completely beautiful now. She doesn't want to marry Papa, but Papa is essentially forcing her to. Rutherford confronts Papa with his knowledge, and the log he's been religiously keeping, blackmailing Papa into providing for the few African children who survived the shipwreck and releasing Isadora from their engagement. Rutherford and Isadora reunite, and she begins to understand how much his experiences have changed him. He now feels that he would like to spend his life with her, while they raise one of the African girls as their own child. Isadora agrees.